The present invention generally relates to devices and procedures suitable for treating patients having ureteral obstructions or the like. More particularly, this invention relates to a ureteral bypass device and procedures for implanting the device, for example, by placing the device under the skin (subcutaneously) or within the abdominal cavity (intra-abdominally) of a patient. The device utilizes catheters and locking/retention mechanisms adapted to retain distal ends of the catheters within the renal pelvis and urinary bladder to avoid inadvertent dislodgement, as well as provide a seal to the kidney and bladder tissues to prevent urine leakage after device placement. The device further includes a port adapted to enable sampling, flushing, and testing the entire device for diagnostic or therapeutic purposes, without the need for invasive and expensive diagnostic methods.
Ureteral obstructions are a major surgical and endourological problem in both human and veterinary medicine. These obstructions can occur for various reasons, the most common of which include but are not limited to ureterolithiasis, urinary tract (intrinsic) or extrinsic neoplasia, and ureteral strictures. The traditional treatment in human medicine has involved the use of minimally invasive endourological procedures, for example, ureteral stenting, lithotripsy, ureteroscopic laser ablation, laparoscopic ureteral resection and anastomosis, and ureteropyelotomy. Minimally invasive treatments have nearly replaced open surgical procedures. In contrast, open surgical procedures such as ureterotomy, ureteral reimplantation and ureteronephrectomy are routinely performed for most causes of ureteral obstructions in companion animals (for example, canine and feline) due to the small nature of the canine (about 1 to 2 mm) and feline (about 0.3 to 0.4 mm) ureter and the minimal options available for interventional devices in animals of this size. Recently, the development of feline and canine double-pigtail ureteral stents has occurred and interventional treatments have become progressively more available. Unfortunately situations arise, particularly in small pediatric and veterinary patients, in whom ureteral decompression is necessary but traditional surgery or endourological procedures are associated with excessive morbidity or mortality, are impossible due to the size or anatomy, or are contraindicated.
In human medicine, if diversion procedures fail, implantation of an externalized percutaneous nephrostomy tube is usually necessary to provide either temporary or long-term drainage of the renal collection system. Placement of an externalized percutaneous nephrostomy tube is also possible in veterinary and pediatric patients for in-hospital stabilization, but is not feasible for long-term use. Major disadvantages associated with long-term use include the need for regular exchanges, the risk of urinary tract infections, urinary leakage and catheter dislodgement, social embarrassment, and an impaired quality of life reported for patients. Subcutaneous (or intra-abdominal) urinary diversion devices can internalize a nephrostomy catheter and allow the urine to drain to the urinary bladder through a subcutaneous tunnel. This eliminates most of the major disadvantages associated with externalized nephrostomy catheters because infection, regular nursing care, leakage, dislodgement, and an impaired quality of life are no longer prominent issues. Subcutaneous (or intra-abdominal) urinary diversion (bypass) devices become a more useful solution to very complicated medical problems associated with veterinary and pediatric patients, for whom externalized catheters are not a realistic option outside of a hospital setting.
A few variations on ureteral bypass devices have been reported in the past, varying from non-locking pigtail catheters, non-fenestrated double-pigtail stents, and non-locking double-lumen catheters with an inner silicone tube and an outer polyester sheath. For example, such devices have been reported or offered by Coloplast A/S. These various devices have been placed with surgical approaches requiring suturing of the tube to the bladder wall and renal capsule to prevent dislodgement and leakage. Short-term and long-term complications have been reported, with the major concerns being dislodgement, occlusion (encrustation), and difficulty in placement. However these devices still remain promising when all other traditional options have failed.
It is clear that there is an ongoing need for devices that are capable of treating various causes of ureteral obstruction, regardless of etiology, patient species, or size, in a rapid, simple, and safe manner. In particular, there is a need for a ureteral bypass device capable of overcoming the shortcomings of the prior art, particularly, dislodgement, discomfort, the currently invasive placement of the device, the large size of the device, as well as the concern for occlusion or encrustation of the device.